1. Field of the Invention
The invention relates to a device for atomizing melts, normal fluids or agglomerates with the aid of ultrasound, which device comprises a first ultrasonic transmitter and an ultrasonic reflector arranged at a distance from it, a standing ultrasonic wave being generated between the two elements into which the medium to be atomized is fed.
2. Background Art
This kind of device, which has proved useful in principle, has been described in the German Patent No. 2,656,330. The reflector is a passive component in this case, and the distance between transmitter and reflector is adjusted via an appropriate mechanical system which only shifts the reflector however. This printed patent specification already mentions that increasing the static gas pressure in the chamber surrounding the ultrasonic wave results in a proportional increase in the sound pressure level. Furthermore, it is mentioned that a gas jet may be injected into the chamber in order to sputter the atomized medium against a cold metal surface, thus causing it to cool down more rapidly.
A similar state of the art is specified in the German Patent No. 2,842,232, from which the idea can be adopted to inject the medium to be atomized into the pressure nodes of the standing ultrasonic wave. Because of the small distances at which the transmitter and the reflector are arranged at the described state of the art, however, liquid matter is deposited on the reflector during atomization, and the reflector is therefore smudged after a certain time. The transmitter on the other hand remains clean because the transmitter plate vibrates and because of the associated ultrasonic wind.
Further drawbacks of the known device result from sound field variations that are mainly induced by temperature variations occurring when the melt jet is injected into the sound field. This causes the parameters of the sound field to change, so that the reflector must be continuously adjusted to maintain the standing wave. As has been mentioned, this adjustment is asymmetrical to the aperture in the housing through which the melt or the medium to be atomized is supplied.